After the discovery of the Standard Model Higgs boson in 2012, we have entered the era of precision measurements of this particle. The decay to two W bosons constitutes the second largest branching ratio for the decay of the Higgs. An overview of the analysis strategy in the Higgs boson cross section measurement in the H->WW(*)->evμv decay channel performed by the ATLAS experiment will be presented. The measurement is made using proton-proton collision data at sqrt(s)=13 TeV collected during 2015 and 2016, corresponding to an integrated luminosity of 36/fb. As the analysis is currently being finalised, focus will be on the analysis method and selections.